4,8-dicyclohexyl-6-hydroxy-2,10-dimethyl-12H-dibenzo[d,g][1,3,2]dioxaphosphocin

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1997-11-17 - 1997-11-21

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Study conducted under GLP according to EU method C.1 on the registered substance itself without analytical monitoring due to the substances intrinsic properties, i.e. poor water solubility. The present proceedings correspond to the preparation of a WAF, which is in line with the recommendations in ECHA's guidance R.7b.

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Version / remarks:

Council Directive 92/69/EEC

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: direct weighing
- Controls: concurrent no treatment, synthetic fresh water in accordance with ISO
- Evidence of undissolved material (e.g. precipitate, surface film, etc): yes

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM
- Common name: Zebra fish
- Strain: Brachydanio rerio HAMILTON BUCHANAN
- Source: Bio International B.V. (Netherlands)
- Age at study initiation (mean and range, SD): ca. 6 months
- Length at study initiation (length definition, mean, range and SD): 2.5 - 3.2 cm
- Weight at study initiation (mean and range, SD): 1.93 - 2.10 g (10 fishes)

ACCLIMATION
- Acclimation period: 4 months
- Health during acclimation (any mortality observed): <2%

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Post exposure observation period:

none

Hardness:

14.1°dH

Test temperature:

21.4°C - 21.8°C

pH:

7.9 - 8.1

Dissolved oxygen:

8.0 - 8.9

Nominal and measured concentrations:

0; 1 mg/L (nominal)

Details on test conditions:

TEST SYSTEM
- Material, size, headspace, fill volume: test vessels (300 x 135 x 200 mm), 5L test medium
- Aeration: ventilated
- No. of organisms: 10 per concentration

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Synthetic fresh water in accordance with ISO.

OTHER TEST CONDITIONS
- Photoperiod: 16h light, 8h dark

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : visible effects on appearance and behaviour of fish, mortality, daily intervals

TEST CONCENTRATIONS
- Test concentrations: 0; 1 mg/L (nominal)

Reference substance (positive control):

not required

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

> 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

behaviour

Duration:

96 h

Dose descriptor:

LC0

Effect conc.:

>= 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

EC0

Effect conc.:

>= 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

behaviour

Details on results:

- Behavioural abnormalities: 10 animals showed normal swimming action at all doses and observation times
- Observations on body length and weight: no relevant deviations from control noted
- Mortality of control: 0%
- Other adverse effects control: none noted
- Abnormal responses: none noted
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: yes, undissolved particles found
- Effect concentrations exceeding solubility of substance in test medium: 1 mg/L

Validity criteria fulfilled:

yes

Conclusions:

The study was conducted under GLP according to EU method C.1 on the registered substance itself without analytical monitoring due to the substances intrinsic properties, i.e. poor water solubility. The present proceedings correspond to the preparation of a WAF, which is in line with the recommendations in ECHA's guidance R.7b. The method is hence to be considered scientifically reasonable. Hence, the results can be considered as reliable to assess the effects of 12H-Dibenzo[d,g][1,3,2]dioxa-phosphocin, 4,8-dicyclohexyl-6-hydroxy-2,10-dimethyl- to aquatic organisms, here, zebra fish. Taking into account the determined effect values after 96h, based on nominal concentrations, i.e. LC50, LC0, EC50, EC0 = resp. ≥ 1 mg/L, based on mortality resp. swimming behaviour, the substance does not need to be classified as aquatic acute cat. 1 according to Regulation (EC) No. 1272/2008. Since 1 mg/L (nominal) was the only concentration tested, a classification as aquatic chronic cat. 2 or lower can not be categorically excluded. However, this concentration resulted in precipitation, i.e. it is above the water solubility of the substance. Based on the procedure as described in the test report, the test solutions need to be considered as a WAF. Hence, it can be assumed that the observed effects, i.e. actually the lacking of mortality or behavioural abnormalities, was observed at concentrations maximally as high as the substance water solubility and the actual LC50 would virtually be above the water solubility of the substance. In this case, referring to the actual concentration, the safety net classification as aquatic chronic cat. 4 would be triggered.

Executive summary:

In a 96-h acute toxicity study, zebra fish (Brachydanio rerio HAMILTON BUCHANAN) were exposed to12H-Dibenzo[d,g][1,3,2]dioxa-phosphocin, 4,8-dicyclohexyl-6-hydroxy-2,10-dimethyl-at nominal concentrations of 0 (control), and 1 mg/L under static conditions. The 96-h LC₅₀was >1 mg/L. The EC_50,EC₀and LC₀values, based on mortality or swimming behaviour, were > resp. ≥ 1 mg/L. Based on the results of this study,12H-Dibenzo[d,g][1,3,2]dioxa-phosphocin, 4,8-dicyclohexyl-6-hydroxy-2,10-dimethyl-would not be classified as aquatic acute cat. 1 to zebra fish in accordance with Regulation (EC) No. 1272/2008. Since the nominal concentration of 1 mg/L is above the water solubility of the test substance, classification as aquatic chronic cat. 4 would be triggered.

This toxicity study is classified as acceptable and satisfies the guideline requirement for an acute toxicity study in fish.

Description of key information

Short-term toxicity to fish: LC50(96h) > 1mg/l, EC0(96h) >= 1mg/l (nominal) for Danio rerio, static, direct weighing of 1 mg/l (EU method C.1, GLP)

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

1 mg/L

Additional information

Nominal concentration is above the water solubility of the test item: Its estimated water solubility is 1.171 E-5 µg/l (no testing could be performed) and the test item needs to be considered as insoluble.